Token (railway signalling)

A token being offered by a signalman on the Keighley & Worth Valley Railway
The moment the train driver picks up the next key token from the hands of the station master at the Bukit Timah Railway Station in Singapore moments after he had dropped off the previous token. This happened whilst the train was still moving fast.

In railway signalling, a token is a physical object which a train driver is required to have or see before entering onto a particular section of single track. The token is clearly endorsed with the names of the section to which it belongs. A token system is more commonly used for single lines because of the greater risk of collision in the event of a mistake being made by a signaller or traincrew than on double lines.